New types of aircraft are being developed which are powered by batteries instead of internal combustion engines. Battery-powered aircraft are attractive because they tend to be lighter than ones which are powered by internal combustion. However, in battery-powered aircraft prototypes, it has been observed that the batteries (or, more specifically, the currents output by the batteries) induce magnetic fields which in turn interfere with instruments on the aircraft. For example, a compass uses the earth's magnetic field to determine the plane's heading and the interfering magnetic field from the batteries can produce a heading error on the order of 2-10 degrees off. Techniques to reduce or zero out the interfering magnetic field produced by the batteries would be desirable.